Burglar alarm



Oct. 31, 1939. o. M. NELSON BURGLAR ALARM Filed Dec. 29, 1958 awf M Nesan Patenteci Oct. 31, 1939 BURGLAR ALARM flsoar M. Nelson, Chicago; Ill; Application Beeernber 29, 1933, Serial No. 248,320

Clainis. This invention relatesto an improved burglar alarm; for Windows of the sliding sash type, adaptedzto, be, associated With an upper and lower sash andto be aetuatedi by the movement of either sash.

More partieularly, it is an aim of this invention to provide awheel having its periphery in frictional engagement with the frame of one sash and supported by another sash Whereby said Wheel Will be revolved by the movernent of either sash, and means eonnecting said Wheel to a to be actuated by the increment thereof to duce an audible alarm.

It is a further object of this invention to provide a burglar alarm of simple compact Construction, Which may be eeonomically manufaetured and Which is adapted to be readily attached to conventional Window sashes of conventional construction and to be actuated there'oy Without modification of the sash frames.

A particular advantage of the invention resides in the fact that due to its size it can be positioned on a Window in such a manner as to be substantially invisible from the outer side of the window 25 so that its eXistence Would not be disclosed until the alarm had been sounded by the opening of the window.

Other objects and advantages of the invention Will hereinafter become more fully apparent from the following description of the drawing, Which illustrates a preferred embodiment thereof, and wherein:

Figure 1 is a top plan view of the invention shown associated With two Window sash frames,

Figure 2 is a front elevational vieW of the same,

Figure 3 is a horizontal central sectional view of the invention, and

Figure 4 is a vertical seotional view taken on the line d-- of Figure 3.

Referring more partieularly to the drawing, Wherein like reference characters designate like or corresponding parts throughout the different views, IU designates generally a portion of a top rail of a lower Window sash frame and ii a portion of the side rail of the upper Window sash frame Which are slidably mounted in the window frame i2 in the conventional manner.

The alarm, designated generally it, includes a bell designated generally M, and comprising the stationary section l Which is preferably circular and provided with an outturned annular flange I 6 the edge of Which is adapted to be slightly spaced from the open edge of the gong section i'i of the bell to form with the section 55 the Chamber i. The general shape of the bell M is conventional and may be vention.

Bell section lt? is rigidly supported by means of the legs it Which are seoured to the outer side the-reef andwhich are removaloly secured at their free ends by means of the fastenings 2ll to the top rail it. Section 65. is provided with a central threaded opening iii in Which is removably mounted the extei iy threaded sleeve 22, Which has its ends projecting outwar site sides of the section iii. Mounted on the threaded end of' the sleeve 22 Which is disposed on the outer side of the bell ili is one end of a bracket Bra'cket is of heok shaped form With the Wheel ?fi journaled on its free end and disposed at right angles to the bell M and positioned so that the periphery 25 thereof is in frictional engagement With the side rail H of the upper sash. Wheel 21% on its outer side is provided With a beveled gear 26, formed integral therewth and adapted to mesh With a smaller beveled gear 27.

The beveled gear 27 has a shaft 28 projecting therefrom Which is journaled in the sleeve 22 and which extends therethrough. The free end of the shaft 28 is threaded o to engage an internally threaded tit 29 Which is formed on the inner side of the gong l l to connect With beveled gear 271.

Gong l is provided With a plurality of indentations forming the inwardly extending projections 39. Secured to the inner end of the sleeve 22 and disposed in the Chamber l8 of the bell M, is a triangular shaped clapper 3l having a central opening 32 through which extends the shaft 28. The three corners of the clapper Si are rolled to form the hammers 33 Which are disposed in the path of the projections s to be engaged thereby When the gong ll moves relatively to the hammers 33.

From the foregoing it Will be seen that When either the upper or the lower sash frame of the Window is moved the rails il! and i i Will be moved relatively to each other so that the Wheel 24 will be revolved by the frictional engagement of its periphery 25 With the side rail H to thereby revolve the gear 27, shaft 28 and the gong il Which is connected thereto. Gong il Will be revolved relatively to the clapper 35 Which is held stationary by the sleeve 22, to Which it is attached, so that the projections 30 will strike the hammers 33 to cause the conventional audible ring of a gong.

The periphery 25 of the Wheel 24 may be serrated for better engagement With the rail lol or may be provided with a removable rubber modified Without aifecting the in- .ly from the oppoforming the alarm' may obviously be made and are contemplated.

I claim as my invention:

1. In a device of the class described, a bell including a stationary element and a gong, means for rigidly snpporting said stationary element on the top of a lower sliding Window frame sash, a sleeve extending through said stationary element and rigdly secured thereto, a bracket mounted at one end on said sleeve, a Wheel journaled on the opposite end of said bracket for frictional engagement With the side rail of the upper sash, said Wheel being provided With a beveled gear on one of its sdes, a beveled bear having a shaft projecting therefrom and journaled in said sleeve, said gong having an internally threaded tit on its inner side for engagement with the th'eaded end of said shaft, and a clapper secured to one end of said sleeve and disposed Within said bell for engagement With portions of said gong, said gears being enmeshed to revolve said gong When the Window sashes are moved relatively to each other.

2. In a burglar alarm for Windows, a supporting member mounted on the top rail of a lower Window sash, a sleeve extending through said supporting member, a braoket supported by said sleeve, a Wheel journaled on said bracket and having its periphery in friotonal engagement with a side rail of an upper sash, said Wheel being provided With an integrally formed beveled gear, and a beveled gear for engagement with said first mentioned beveled gear provided with a shaft journaled in said sleeve, a gong secured to the free end of said shaft to be revolved by the movement of said gears, and a clapper connected to said sleeve for engagement With said gong.

3. A device as in claim 2, said clapper being triangular in shape and provided With enlarged portions at its corners forming hammers, and said gong being indented to provide inwardly projecting elements for engagement With said hammers.

4. An alarm comprising a Wheel having its periphery in frictional engagement With a side rail of a Window sash, means for supporting and journaling said Wheel, said Wheel being provided With an integrally formed beveled gear on one of its sides, a beveled gear enmeshed with said first mentioned gear, a shaft secured to and projecting from said last mentioned beveled gear, means for supporting and journaling said shaft, said last mentioned means being mounted on a Window sash frame, a gong mounted on the free end of said shaft to be revolved by the operation of said gears, said gong having a plurality of spaced ndentations, and a fixed clapper supported by said last mentioned means and provided With a plurality of hammers projecting into said gong for engaging said indentations When the gong is revolved.

OSCAR M. NELSON. 

